Fracturing using a plug and perforate method is well known. In this method barriers are delivered with a perforating gun and after the barrier is set the gun is repositioned and fired followed by a pressure treatment against the barrier. This process is repeated in an uphole direction until the entire zone of interest is treated. After that the plugs are generally drilled out. The process of drilling out the plugs is time consuming and the cost of the plugs can be substantial depending on the size of the borehole and how many plugs are required for the interval to be treated.
Ratchet mechanisms have been used in the past for allowing relative movement in a single direction. Some devices in the past have used ball seats in tools as distinct structures from ratchet rings. Generally ratchet rings are internal tool components that permit unidirectional relative movement between parts. Some examples are: U.S. Pat. No. 7,861,781; US 6,116,336 (FIG. 9); US 8,887,818 (FIG. 5); US 9,045,963 (FIG. 27); US 2,490,350 (FIGS. 2 and 4 and EP 0431689 A1 (FIG. 1).
What is needed and provided by the present invention is an economical way to provide barriers in the borehole coupled with a way they can be rapidly removed such as by drilling out or by other means such as disintegration. The barriers have a scroll shape to allow for radial expansion with one or opposed ratchet features to lock the enlarged dimension against a surrounding borehole. The scroll exterior can have hard facing or carbide or other materials that preferably penetrate the inside wall of the surrounding tubular for additional support. Expansion can be with a subterranean tool such as an inflatable, or potential energy trapped in the scroll can be released or the scroll can be made of a shape memory alloy that grows to meet the surrounding borehole when exposed to well temperatures above the critical temperature of the material. The scroll is flexible to tolerate some out of roundness of the surrounding tubular and the built in seat at an end allows a ball to land to stop most of the flow so pressure can build up for the treatment of the formation. In many applications complete sealing is not needed as long as high flows under high pressure can enter the formation. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.